In suspension systems that have a coil spring shock absorber coupled directly to a frame on one end and coupled to a wheel or swing-arm on the opposite end, herein referred to as a direct impact shock system, the response of the shock absorber is not linear over the range of travel of the shock absorber. At the beginning of compression, the shock absorber exhibits a lag in response to an impact which presents undesirable performance characteristics such as spongy or imprecise control of damping response. As the coil nears or reaches full compression, the shock absorber exhibits undesirable kickback which causes motion instabilities and jarring. At full compression, the shock absorber is no longer able to respond to greater impact loads leading to loss of damping performance. In other words, the response of coil shock absorbers to loading and impact is non-linear over the range of compression, otherwise known as the shock absorber travel, of the coil spring. Therefore, the desired performance of the direct impact shock system may be presented when the shock absorber is within a narrow range between the fully extended and fully compressed, referred to as the “sweet spot”. In force loading situations where the shock absorber travel is large, it is likely that the shock absorber will travel outside this sweet spot of desired performance and into the realm of poor performance.
The coil spring shock absorber is not the only device that exhibits the above described non-linear response. Such a response may be found in other shock absorber systems, including, but not limited to, gas and hydraulic-type shock absorbers and combinations of which that include a coil spring.
Accordingly, there is a need in the art for improved apparatus and methods for suspension systems.